Presently, aircraft windows are provided in modular form for retrofitting existing aircraft or finishing out newly manufactured aircraft. Because of the unique demands of the aircraft's operating environment, aircraft windows must be lightweight, compact, modular, easy to assemble, durable and have few parts.
Typically, present aircraft window shades are powered by the aircraft's electrical system, or manually operated by the passenger. These shades are raised between an upper and a lower position. Many aircraft are presently fitted with shades located between an outer and an inner pane such that the aircraft passenger does not have direct access to the shade itself; raising and lowering the shade must be effected through either a control switch which engages an electric motor or, in the case of a manually operated window, a lever which is manually positioned by the passenger.
Typically the course of a flight, individual passengers will operate their own window shades so that, at any given time, each shade will be in a different position. However, there are occasions when it is desirable for the pilot or crew to simultaneously open or close all window shades in the aircraft. Electrical control of all aircraft window shades is also required if the pilot or crew operates them en masse. This may be difficult to accomplish successfully, since the pilot can only view those window shades near to his seat and not those in the remainder of the aircraft. Because of mechanical friction and those variations introduced by voltage fluctuations along the aircraft electric power buss, electrical window shades throughout the aircraft will often each operate at slightly different speeds. This being the case, a pilot acting to close or open all of the aircraft's window shades can often not be certain that other window shades in the aircraft are similarly situated to his own.
While the raising and lowering of window shades using electrical controls is known, such devices are usually much more complicated and expensive than would be tolerated in the art of aircraft window design. An example of such a device is disclosed in U.S. Pat. No. 4,706,726 (Nortoft, 1987). This patent addresses the problem of raising and lowering a window along with the separation of slat control from the operations of window shade movement. Such a device would be impractical for use with aircraft windows, since the number of parts required militates against the simplicity, reliability, and lightweight components required for aircraft.
Applicants' invention addresses, in the various embodiments of the aircraft window shade speed control illustrated, described and claimed herein, a problem heretofore either unsuccessfully or not addressed by others in the market.